Circulation and Blood

Flashcards by , created about 6 years ago

Cambridge IGCSE Biology Flashcards on Circulation and Blood, created by ashley.amber on 05/29/2013.

Created by ashley.amber about 6 years ago
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Question Answer
what is the name of the liquid part of the blood? what is it's function? plasma- mainly made of water, carries blood cells around the body , distributes heat, carries dissolved nutrients, hormones, urea and CO2
describe a red blood cell bioconcave- disc like. no nucleus. transports 02. contains haemoglobin which loads 02 in the lungs and unloads in other areas of the body
what are the 2 types of white blood cell? lymphocytes and phageocytes
describe a lymphocyte same size as a red blood cell, has a nucleus. produces antibodies
describe phageocytes larger cells with a nucleus. engulfs bacteria
what is the function of platelets? fragments of other cells. when the skin is cut, the air stimulates them to produce a chemical which causes fibrin to be formed. fibrin forms a network across the wound, trapping red blood cells. this forms a clot.
what does blood clotting prevent from happening to the cut? blood loss and entry of patheogens
what is oxyhaemoglobin? haemoglobin which has bound with oxygen due to a high 02 concentration in the blood
what happens when there is low concentration in the tissues? oxyhaemoglobin unloads it's oxygen and turns back into haemoglobin
how is a red blood cell adapted to carry blood? no nucleus- more room for haemoglobin. high surface area to volume ration- large surface area for diffusion. thin membrane- short distance for diffusion
what happens in phagocytosis? when a bacteria enters the blood, the phagocyte cell surrounds and engulfs it into it's vacuole, where digestive enzymes are able to destroy the bacteria
what percentage of white blood cells are phagocytes? 70%
what is an antibody? soluble proteins made by lymphocytes, which can pass through plasma
what is an antigen? a chemical marker on a bacteria's surface, which are recognized by antibodies.
once an antibody has stuck to the surface of an antigen, give 3 ways it can destroy it 1) causing the bacteria to stick together,allowing phagocytes to engulf them more easily. 2) causing bacterial cells to burst 3) neutralizing toxins produced by pathogens
what is a memory cell? a cell making us immune to a disease. when a bacteria enters the body, some lymphocytes don't kill it straight away, but develop memory cells to prevent future infection
how does the memory cell keep us immune from the disease? they stay in the body for many years, so if the same bacteria reinfects, the lymphocyte can quickly produce the antibody to destroy it
how does a vaccination work? a weakened strain of a disease is injected into the blood stream, so lymphocytes can make the necessary memory cells
we need a circulatory system for... transporting O2 from the lungs to the body, CO2 from the body to the lungs nutrients from the gut to the body urea from the liver to the kidneys distributes heat, hormones and antibodies
DOUBLE CIRCULATION CONSISTS OF: pulmonary circulation systemic circulation PC- blood circulated through the lungs where it is oxygenated SC- blood circulated through all other parts of the body where it unloads oxgyen
double circulation is more efficient because heart pumps blood twice, higher pressure maintained. blood can travel quicker
what do the following vessels do? a)arteries? b)veins? c)capillaries? a) carry blood away from the heart b) carry blood towards the heart c) carry blood through organs
what do the following vessels do? a)arteries? b)veins? c)capillaries? a) carry blood away from the heart b) carry blood towards the heart c) carry blood through organs
what allows the heart to pump blood around the body at different speeds and pressures? the walls of the heart are made from cardiac muscle, which relaxes and contracts to let blood through
a) what divides the heart into two section? b) name the 2 sections? a) the septum b) the left and right ventricles
why is the wall of the left ventricle thicker than the wall of the right ventricle? because the RV only pumps blood to the heart, where as the LV pumps blood to all the other organs- it therefore requires more pressure and so the walls are thicker
why are the atria walls thin? so they can be stretched to recieve blood, and contract to push blood into the ventricles
what is normal heart rate? about 70bpm
what happens to our heart rate when we excersise and why? muscles release more energy and need more 02 for aerobic respiration. to do this, the number of bpm must increase as well as the volume of blood pumped with each beat.
what happens to heart rate when we sleep? it decreases because we are moving more slowly, release less energy so need less 02
what does the accelerator nerve do? what does the decelerator nerve do increases heart rate- causes heart to beat with more force and increases blood pressure. it does the opposite
why does venous blood have lower pressure than arterial blood? because It's only being pumped to the heart, where as arterial blood is pumped to all other parts of the body